/*
 * Copyright (C) 2012-2016 Markus Junginger, greenrobot (http://greenrobot.org)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.greenrobot.eventbus;

import java.util.ArrayList;
import java.util.List;

final class PendingPost {
  private static final List<PendingPost> pendingPostPool = new ArrayList<PendingPost>();

  Object event;
  Subscription subscription;
  PendingPost next;

  private PendingPost(Object event, Subscription subscription) {
    this.event = event;
    this.subscription = subscription;
  }

  static PendingPost obtainPendingPost(Subscription subscription, Object event) {
    synchronized (pendingPostPool) {
      int size = pendingPostPool.size();
      if (size > 0) {
        PendingPost pendingPost = pendingPostPool.remove(size - 1);
        pendingPost.event = event;
        pendingPost.subscription = subscription;
        pendingPost.next = null;
        return pendingPost;
      }
    }
    return new PendingPost(event, subscription);
  }

  static void releasePendingPost(PendingPost pendingPost) {
    pendingPost.event = null;
    pendingPost.subscription = null;
    pendingPost.next = null;
    synchronized (pendingPostPool) {
      // Don't let the pool grow indefinitely
      if (pendingPostPool.size() < 10000) {
        pendingPostPool.add(pendingPost);
      }
    }
  }
}
